1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device and a semiconductor device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2010-267674 discloses a method for manufacturing a semiconductor photonic device in which side surfaces of a semiconductor mesa on a substrate are buried in a Fe-doped semiconductor layer. In the method, the Fe-doped semiconductor layer has a first buried layer and a second buried layer. The first buried layer is formed on the semiconductor mesa and the second buried layer is formed on the first buried layer.
In the semiconductor photonic device described in Japanese Unexamined Patent Application Publication No. 2010-267674, the first buried layer is formed by supplying the growing reactor with a raw material gas alone. No halogen-containing gas is supplied for forming the first buried layer. The second buried layer is formed by supplying the growing reactor with a raw material gas and a halogen-containing gas. The halogen-containing gas is effective in leveling the top surface of the second buried layer. However, the supply of a halogen-containing gas during the formation of the first buried layer causes abnormal growth of the first and second buried layers on the mesa.
Tatsuya TAKEUCHI et. al., “Substrate Orientation Dependence of Fe Doping in MOVPE-Grown InP”, Extended Abstracts of the 1993 International Conference on Solid State Devices and Materials, 1993; pp. 285-287 discloses a crystal growth method for InP containing Fe. TAKEUCHI et. al. states that Fe in InP includes electrically-active Fe that contributes to the semi-insulating properties of InP (hereinafter referred to as active Fe) and Fe that does not contribute to the semi-insulating properties of InP. The concentration of active Fe depends on the flow rate of an Fe raw material supplied to the growing reactor. In addition, the concentration of active Fe depends also on the crystalline orientation of InP. The concentration of active Fe saturates at a certain flow rate of the Fe raw material, and the saturation concentration of active Fe depends on the crystalline orientation of InP.